From: Rolf Østvik <rolfostvik@yahoo.no>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-performance@postgresql.org
Subject: Re: Worse perfomance on 8.2.0 than on 7.4.14
Date: Mon, 1 Jan 2007 16:19:05 +0100 (CET)
Message-ID: <20070101151905.55545.qmail@web26309.mail.ukl.yahoo.com> (raw)
In-Reply-To: <4049.1167585088@sss.pgh.pa.us>
--- Tom Lane <tgl@sss.pgh.pa.us> skrev:
> Rolf =?iso-8859-1?q?=D8stvik?= <rolfostvik@yahoo.no>
> writes:
> > I have a simple query which uses 32ms on 7.4.14
> and 1015ms on 8.2.0.
>
> There's something awfully strange about that 8.2
> plan --- if it knew
> that it'd have to scan all of uut_result_subset
> (which it should have
> known, if the stats were up-to-date),
I can't really see the need for it to do an sequence
scan, but that is me not knowing how things work.
>why did it use
> an indexscan
> rather than a seqscan? Are you sure you haven't
> tweaked any parameters
> you didn't tell us about, such as setting
> enable_seqscan = off?
I haven't touched enable_seqscan.
It could be that i have forgotton to tell you about a
parameter i have tweaked, but i doubt it.
Best regards
Rolf Østvik
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To: pgsql-performance@postgresql.org
Cc: rolfostvik@yahoo.no, tgl@sss.pgh.pa.us
Subject: Re: Worse perfomance on 8.2.0 than on 7.4.14
In-Reply-To: <20070101151905.55545.qmail@web26309.mail.ukl.yahoo.com>
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